EMC philosophy applied to design the grounding systems for gas insulation switchgear (GIS) indoor substation

This paper presents the EMC (Electromagnetic Compatibility) philosophy applied to design the grounding systems of GIS Insulated Substation - GIS indoor substation. The grounding systems are characterized by the following subsystems: Main Grounding grid (60 Hz Grounding System), Equipotential Grounding grid (HF Grounding system) and Lightning Grounding system. The real case measurements for 100 MVA, 69/13.8 kV GIS indoor distribution substation indicated that adopted EMC philosophy is appropriate because the maximum measured potential difference among the various grounding systems of GIS indoor substation was approximately zero volts and the maximum measured touch voltage was less than 1.4 volts.